Manufacture of nonsplintering glass sheets



1929. G. E. HEYL MANUFACTURE OF NONSPLINTERING GLASS SHEETS Filed Sept.18, 1928 2 Sheets-Shee 6 n 1W q m 0 f W I e J a EBA M k L6 a i ,0 10

[m/enzm." ear-9c [/rrorJA gy/ A TT o a N 2T5 Aug. 20, 1929. e. E. HEYLMANUFACTURE OF NONSPLINTERING GLASS SHEETS Filed Sept. 18, 1928 2Sheets-Sheet therein after the surfaces of sheets therein beingsubjected to conjoint what is a greater Patented At 20, 1929.

UNITED STATES PATENT OFFICE.

GEORGE EDWARD HEYL, OF WESTMINSTER, LONDONQENGLANDQ MlfNUFACTURE 0FNONSPLINTERING GLASS SHEETS.

Application filed September 18, 1928, Serial No.

This invention is an improvement in or modification of the process ofmanufacturing nonsplintering glass sheets dc cribed and claimed in thespecification of ;y6copending application for Patent No. 306,1 Q.

' In the said specification is described a process of manufacturingcompound interadherent sheets of glass and cellulose derivativecomposition, such as cellulose acetate, in which the glass and cellulosederivative composition sheets, formed with'adherent films 0n thecellulose derivative composition by moistening with a solventorsoftening liquid, are heated and subjected to direct pressing by afluid under pressure whilst shielded from contact therewith by beingenclosed in a pliable'bag.

Now when a number of compound sheets are to be pressed simultaneously inthe same bag it is diflicult to insert them separately the cellulosederivative composition sheets have been moistened with and, renderedsoft by the solvent or softening liquid. Moreover, and disadvantage,such sepa rately inserted moistened sheets cannot be freed from bubblesof air which become trapped between the sheets and impair the finishedproduct.

Now according to the present invention, the bag, enclosed in which thesheets are subsequently subjected tosdirect fluid pressing, is itselfsheets are immersed in the solvent or softening liquid, and suchimmersion is effected with the sheets standing on edge, and, inaddition, suction is initially applied to the top of the bag afterclosure, whereby the external atmospheric pressure expresses the excessof such liquid upwards from the sheets in the bag, prior to the bag andthe direct fluid pressing and heating.

The bag is held distended by a rigid channelled frame in which the glassand cellulose derivative composition sheets are inserted and held onedge. The cellulose derivative composition sheets in the frameareinitially separated by spacing -members from the glass sheetstherein. These spacing members are removed prior to the application ofsuction and pressing.

To minimize entanglement of bubbles of air between the sheets, thesheets are preferably inserted in the frame and bag prior place at thebottom utilized as the vessel in which the 306,751, and in diam BritainAugust 29, 1928.

to liquid'being introduced therein, and introduction of the liquidpreferably takes of the bag, so that its level ascends therein. To avoidresidual air in the closed bag being drawn in between the sheets on theliquid being pressed out by the external atmospheric pressure oncollapse of the sides of the bag under suction, the suction is, at anyrate initially, applied to the top of the ba The manner in which theinvention is carried into effect is described in more detail with theaid of the accompanying drawings, in which Fig. 1 is a sectional itsappurtenances with therein and prior to the ing members.

Fig. 2 is a sectional plan similar to Fig. 1 but with the spacingmembers removed and the sides of the bag collapsed under externalatmospheric pressure.

On a smaller scale Fig. 3 is an elevation and Fig. 4 a plan of thebag-distending channelled frame.

Fig. 5 is an elevation of the bag in position in a steam pan orautoclave, the latter being shown in section by dot-dash lines.

plan of the bag and the sheets contained a is the india rubber bag. Thisbag a is held distended by an open sided channelled frame 6, shownseparately in Figs. 3 and 4.

The distended bag a is held in an open sided wooden crate o, the opensides of which are temporarily closed by slidingly inserted boards (1.

A pipe 6 connects to a tank 7' and the pipe nipple g.

As shown in Fig. 5, an upright pipe h is connected to the pipe e and isprovided with a cut-off cock i, and the pipe 6 is provided with cut-ofi'cocks j and it, one on each side of its connection to theupright ipe h.Z are sheets of glass inserte in the distending frame 5 within the baga, the mouth of which is initially open. m are sheets of cellulose.derivative composition inserted be tween each alternate pair of glasssheets I and separated therefrom by corrugated perforated zinc orvulcanite spacers n.

As the product to be made is a plurality of compound sheets eachcomposed of two sheets of glass with an interadherent interposed sheetof cellulose derivative composithe bottom of the bag an top of the bag ahas a removal of the spaction, there are obviously double the number ofsheets of glass than sheets of cellulose derivative composition.

After the sheetsl and m and spacers n have been inserted in the frame I)and bag at, and whilst the mouth of the bag is still open, softening orsolvent solution is poured into the pipe h, for instance with the aid ofa funnel o inserted in a short rubber hose pipe 0 on the pipe h, Fig.-5, the cocks '21 and 1' being open and the cock is closed.

.The liquid poured into the pipe h de- 'the spacers n are withdrawn frombetween the sheets. v

1 After removal of the spacers a the sheets l and m are then pushedtogether by hand, and the resulting free space within the frame 6 oneach side of the pack of sheets Z, m, is

approximately filled out by inserting rubber mats 1), shown in Fig. 2. Atop plate or cover 6 shown in section in 3, is then placed over andcloses the previously open top of the'frame b.

The mouth of the bag a is then closed and is clamped hermitically closedby clamping bars 9 drawn togeiher'by nuts g and bolts 9 as shown in Fig.5. a

After the mouth of the bag a has been hermetically closed, the rubberhose pipe 0 on the pipe 72) is bent over and fitted on to the beforementioned pipe nipple g at the top of the bag a.

With the cock 7' of the pipe e closed and the cocks'i and is open, thetank f is by a pipe I placed in communication with a suction air pumpmaintaining a vacuum of about 26 inches of mercury.

Suction thus is applied to the top of the bag a, and on the sides of thebag collapsing inwards, as indicated in Fig. 2, under the externalatmospheric pressure, air contained in' the bag 01, which air isobviously above the liquid thereinyis the first to be forced out. Thusany liability of the air being drawn down between the sheets is avoided;

On complete collapse of the sides ofthe bag and consequently after allair and the major portion of the liquid has been drawn off from the bag,the cock is again opened;

This permits residual liquid gradually to drain out of the bag under thesqueeze exerted by the atmospheric pressure. It is immaterial whetherthe cock e is then still open or is closed. p v

On collapse of the sides of the bag on, the boards (5, or one thereof,is withdrawn from the crate 0, thus leaving the bag 01 freely v exposedto external pressure at the open side or sides of the crate 0.

- Whilst the suction is still maintained on the interior of theebaga,and after about 30 minutes has been allowed to elapse duringwhich thesheets and bag are draining,

external steam pressure is applied to the bag a and the pack of sheetstherein, by admitting steam under pressure by a pipe 7' to the interiorof a then closed autoclave r in which the crate c is mounted.

' The bag a is subjected to the steam for about 15 minutes, the steampressure radu; ally being brought up to 35 poun s per square inch aboveatmospheric pressure during the first 7 minutes and maintained at thits1pressure for the remainder of this per1o The pairs of sheets of glass Zwith a sheet of cellulose derivative composition-m interposed, are eachformed into a thoroughly interadherent compound sheet by the pressureand heat of the steam, and can be immediately removed from the bag.

The upper surface of the base of the chan 'nelled frame I) is providedwith transverse immersing said sheets on edge in liquid within said bag,closing said bag, and applying. suction initially to thetop of said bagprior to subjecting said bag and sheets to saidconjoint pressing.

2. A method of avoiding the trapping of air bubbles between thecomponent sheets of a plurality of compound sheets of glass and ce ulosederivative composition conjointly pressed in a fluid-tight bag,consisting in arranging said sheets on edge within'said bag, admittingliquid at the bottom of said bag to rise and submer e said sheets,closing said bag, and applying suction initially to the top of saidbagprior to subjecting said bag and sheets to said conjoint pressing.

3. An apparatus for moistemng and draining a plurality of sheets ofglass. and cellulose derivative composition, consisting of a Ifluid-tight bag, pipe connections at the top and bottom of said bag, anupright channelled frame within and distending said bag and in whichsaid sheets are arranged on edge, and a o te containing said bag.

In testimon whereof I'have signed my name to this-specification.-

GEORGE EDWARD HEYL,

